flex(justify=flex-start, align=flex-start) {
  display flex
  justify-content: justify
  align-items: align
}
.flex-1 
  flex(flex-start, center)
.flex-2
  flex(center, center)
.flex-3
  flex(space-between, center)

.btn
  cursor pointer
.btn__default
  cursor pointer
  background: red
  color #fff
  font-size 14px
  display inline-block
  min-width 80px
  text-align center
  height 32px
  line-height 32px
  border-radius: 4px